Maryland's congressional delegation cruised to victory in Tuesday's primary, leaving Democrats positioned to dominate the state's House seats even in a year that's shaping up to be promising for the Republicans nationally.

Six of eight incumbents representing the state in the House of Representatives — five Democrats and one Republican — faced challengers, but most of them were not well known and raised too little money to pose serious threats.

In an election year that could have a profound effect on President Barack Obama's final years in the office — as well as on the fate of efforts to overhaul immigration laws and the U.S. tax code — Democrats and Republicans are battling for control of the Senate and the GOP is hoping to add to its majority in the House.

But little of that action is likely to play out in deep-blue Maryland, where congressional districts redrawn after the 2010 census have put most incumbents into safe seats.

Two newcomer candidates in Maryland — Democrats Paul Rundquist and Matthew Molyett — ran campaigns focused on the controversy surrounding domestic spying by the National Security Agency. Rundquist challenged Ruppersberger, the top Democrat on the House Intelligence Committee, in a district that is home to the agency's headquarters at Fort Meade.

Molyett ran against Sarbanes. Sarbanes won the nomination despite voluntarily limiting political donations to draw attention to his efforts to reform federal campaign finance rules.

"One common refrain I am hearing from voters of all political stripes is that they are frustrated with the influence big money politics has on our democracy," he said in a statement. "I'm working hard to fight back against this influence."

In Harris' district, which includes the Eastern Shore and portions of Harford, Baltimore and Carroll counties, Democrats witnessed a spirited contest between John LaFerla, a Chestertown physician, and retired attorney Bill Tilghman of Centreville. Early results showed Tilghman with a slight lead.

LaFerla ran an unsuccessful primarycampaign in 2012, and then ran as a write-in candidate with Democratic Party support when the winner, Wendy Rosen, withdrew from the race in September amid allegations that she voted in the 2006 and 2008 elections in both Maryland and Florida.

Harris' district became far more Republican when the state's electoral map was redrawn in 2011, transforming what was a swing district in the 2008 and 2010 elections into the state's only GOP stronghold.

Harris, an anesthesiologist from Cockeysville, won in 2012 with 63 percent of the vote.

Nationally,Republicans are trying to expand their 34-seat majority in the House and pick up the six seats they need to claim control of the Senate, an outcome that would likely make it still more difficult to reach bipartisan agreement on even mundane issues.

Neither of Maryland's senators is up for re-election this year. Sen. Barbara A. Mikulski will next face voters in 2016 and Sen. Ben Cardin's next election is in 2018.

There was less drama in Maryland's congressional primaries this year than in the 2012 election, when Delaney, then a newcomer, upset the state's Democratic establishment by trouncing then-state Sen. Rob Garagiola. The Potomac financier went on to beat 10-term Republican Roscoe G. Bartlett in the general election.

This year, Delaney will face Republican Dan Bongino of Severna Park, a former Secret Service agent who won the GOP primary for Senate to run against Cardin in 2012. Bongino, who frequently fills in as a guest host on Sean Hannity's conservative radio program, is an aggressive campaigner and has raised more than $530,000 since early 2013.

State Republicans said they were focusing their resources on Bongino in an effort to reclaim the district, which includes Western Maryland and portions of Frederick and Montgomery counties.

"It's the only one we have any reasonable shot of winning," said Joe Cluster, executive director of the Maryland Republican Party. He said redistricting had made the state's other Democratic-held seats difficult to break into.

But while it might be the GOP's best opportunity, Bongino nevertheless has a steep climb. For starters, Delaney beat Bartlett last time with nearly 59 percent of the vote — a hefty margin. He has shown a capacity to raise significant sums of money — about $2 million in 2012 — and toaugment that haul with his own personal wealth.

And Delaney has taken a centrist and frequently bipartisan approach during his first term, which is likely to appeal to independent voters.

"I feel like I'm doing what I said I was going to do," Delaney said. "I think the country is so desperate for people who are going to try to work on constructive solutions."

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